U.S. patent application number 14/552459 was filed with the patent office on 2015-05-28 for secure human fingerprint sensor.
The applicant listed for this patent is SHENZHEN HUIDING TECHNOLOGY CO., LTD.. Invention is credited to Yi He, Bo Pi.
Application Number | 20150146944 14/552459 |
Document ID | / |
Family ID | 53180278 |
Filed Date | 2015-05-28 |
United States Patent
Application |
20150146944 |
Kind Code |
A1 |
Pi; Bo ; et al. |
May 28, 2015 |
SECURE HUMAN FINGERPRINT SENSOR
Abstract
Devices, systems, and techniques are provided for performing
human fingerprint detection and authentication for authenticating a
request to access a locked mobile device equipped with a
fingerprint detection module. In one aspect, responsive to
detecting a contact from an object with the fingerprint detection
module, described technique can be used to determines whether the
contact from the object is from human skin. When determined that
the detected contact from the object is from human skin, a presence
of a human fingerprint can be detected from the object making
contact. The detected fingerprint data can be obtained from the
object and compared against stored fingerprint profiles associated
with an authorized user of the locked mobile device. Based on the
comparing, the request to access the locked mobile device can be
granted.
Inventors: |
Pi; Bo; (Carlsbad, CA)
; He; Yi; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHENZHEN HUIDING TECHNOLOGY CO., LTD. |
Shenzhen |
|
CN |
|
|
Family ID: |
53180278 |
Appl. No.: |
14/552459 |
Filed: |
November 24, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61908026 |
Nov 22, 2013 |
|
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|
62031833 |
Jul 31, 2014 |
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Current U.S.
Class: |
382/124 |
Current CPC
Class: |
G06F 21/83 20130101;
G06K 9/0004 20130101; G06K 9/00053 20130101; G06K 9/00087 20130101;
H04L 63/0861 20130101; G06F 21/32 20130101 |
Class at
Publication: |
382/124 |
International
Class: |
G06K 9/00 20060101
G06K009/00 |
Claims
1. A method for authenticating a request to access a locked mobile
device equipped with a fingerprint detection module, the method
comprising: responsive to detecting a contact from an object with
the fingerprint detection module, determining whether the detected
contact from the object is from human skin; responsive to
determining that the detected contact from the object is from human
skin, detecting fingerprint data from the human skin; obtain the
detected fingerprint data from the human skin; comparing the
obtained fingerprint data against stored fingerprint profiles
associated with an authorized user of the locked mobile device; and
granting or denying the request to access the locked mobile device
based on the comparison of the obtained fingerprint against stored
fingerprint profiles associated with an authorized user of the
locked mobile device.
2. The method of claim 1, comprising: detecting a signal from a
metal ring touch sensor on the fingerprint detection module
indicating a contact from the object.
3. The method of claim 2, wherein detecting the signal includes
detecting an increase in a capacitive load coupled to the metal
ring using circuitry integrated with the fingerprint detection
module.
4. The method of claim 1, wherein the contact includes a touch by a
human finger.
5. The method of claim 1, wherein determining whether the detected
contact from the object is from human skin includes: emitting
detection light of at least one selected wavelength using one or
more light emitting sources within the fingerprint detection
module; detecting at least a portion of the emitted detection light
which is reflected off of the object making contact with the
fingerprint detection module using at least one photodetection
element within the fingerprint detection module; and processing
output signals responsive to detecting of the at least a portion of
the detection light from the at least one photodetection element
corresponding to the at least one selected wavelength.
6. The method of claim 5, wherein the at least one selected
wavelength includes two wavelengths; and comparing a signal ratio
of output signals corresponding to the two selected wavelengths
with a predetermined value of the same signal ratio calibrated from
human skin.
7. The method of claim 1, wherein the determining whether the
detected contact from the object is from human skin is performed
using a signal processing circuit integrated with the fingerprint
detection module.
8. The method of claim 1, wherein the detecting presence of
fingerprint data from the human skin includes: measuring
one-directional (1D) skin profile of the human skin; and
determining whether the 1D skin profile substantially matches a
human fingerprint.
9. The method of claim 1, wherein detecting the fingerprint data
from the human skin includes using a detection circuit integrated
with the fingerprint detection module.
10. The method of claim 1, wherein the comparing the obtained
fingerprint data against stored fingerprint profiles associated
with an authorized user of the locked mobile device includes using
an application processor of the mobile device.
11. The method of claim 5, wherein granting or denying the request
to access the locked mobile device based on the comparing includes:
based on the comparing, detecting a presence of a heartbeat signal
from the human skin; and based on the detected presence of a
heartbeat signal, granting the request to access the locked mobile
device.
12. The method of claim 11, wherein the detecting a presence of a
heartbeat signal from the human skin comprises measuring relative
light reflection of the human skin of the detection light
corresponding to the at least one selected wavelength emitted by
the one or more light emitting sources.
13. The method of claim 11, wherein the detecting a presence of a
heartbeat signal from the human skin indicates whether a live
person is associated with the detected human fingerprint.
14. The method of claim 11 where the light emitting source includes
one or more light emitting diode (LED) lights.
15. The method of claim 11 where the light emitting source is
modulated at a predetermined frequency and a detection circuit
demodulates this frequency.
16. A fingerprint detection module, comprising: a printed circuit
board; a fingerprint sensor chip disposed over the printed circuit
board and configured to collect fingerprint data; a protective
layer disposed over the fingerprint sensor chip to protect the
fingerprint sensor chip; and a touch sensor disposed substantially
next to the protective layer to detect a contact from an object
making contact with the fingerprint detection module.
17. The fingerprint detection module of claim 16, wherein the touch
sensor comprises a conductive electrode.
18. The fingerprint detection module of claim 16, further
comprising touch sensing circuitry communicatively coupled to the
touch sensor to detect a signal indicative of an object in contact
with the touch sensor.
19. The fingerprint detection module of claim 18, wherein the touch
sensing circuitry is configured to detect a contact from an object
by detecting an increase in a capacitive load coupled to the
conductive electrode.
20. The fingerprint detection module of claim 19, further
comprising detection circuitry integrated with the fingerprint
sensor chip to detect a presence of fingerprint data from the
object.
21. The fingerprint detection module of claim 16, further
comprising an optical detection module that includes: one or more
light emitting sources located on the substrate carrier and
underneath the protective cover; at least one photodetection
element integrated with the fingerprint sensor chip and underneath
the protective layer; and a signal processing circuit integrated
with the fingerprint sensor chip.
22. The fingerprint detection module of claim 21, further
comprising a colored layer coated on the bottom surface of the
protective cover, wherein the colored layer contains micro-holes in
a first region directly above the one or more light emitting
sources and a second region directly above the at least one
photodetection element to allow light to pass through the colored
layer in the first region and the second region.
23. The fingerprint detection module of claim 21, further
comprising a colored layer coated on the bottom surface of the
protective layer, wherein the colored layer is transparent with a
nonvisual wavelength light in a first region directly above the one
or more light emitting sources and a second region directly above
the at least one photodetection element to allow certainly
wavelength light to pass through the colored layer in the first
region and the second region.
24. The fingerprint detection module of claim 21, wherein the one
or more light emitting sources are configured to emit detection
light comprising at least one wavelength; and wherein the at least
one photodetection element are configured to receive and detect at
least a portion of the detection light which is reflected off of an
object making contact with the fingerprint detection module.
25. The fingerprint detection module of claim 24, wherein output
signals from the at least one photodetection element in response to
the detected light are used to determine one or both of: whether
the detected contact from the object is from human skin; and
whether a presence of a heart beat is detected from the object.
26. The fingerprint detection module of claim 16, wherein the
module is configured to combine the collected fingerprint data from
the fingerprint sensor chip and the detected contact from the touch
sensor to deny a person's access when the collected fingerprint
data matches stored fingerprint data of an authorized user's
fingerprint pattern while the detected contact fails to indicate
the contact is from a live person.
27. The fingerprint detection module of claim 16, further
including: an authentication processor coupled to the fingerprint
sensor chip and the touch sensor and is configured to combine the
collected fingerprint data from the fingerprint sensor chip and the
detected contact from the touch sensor to authenticate a person
when the collected fingerprint data matches stored fingerprint data
of an authorized user's fingerprint pattern and the detected
contact indicates the contact is from a live person.
28. A fingerprint detection module, comprising: a touch sensor
including a metal ring configured to detect a contact from an
object making contact with the fingerprint detection module; a
fingerprint pattern sensor that includes a sensor array configured
to read a fingerprint pattern and a fingerprint pattern processor
configured to determine whether the read fingerprint pattern
matches stored information of an authorized user's fingerprint
pattern to provide a fingerprint pattern authentication output; an
optical sensor module that produces probe light at one or more
optical wavelengths to which the user's skin produces different
optical responses at the one or more optical wavelengths due to
presence of blood under the skin, the optical sensor module
including an optical detection unit configured to receive a
reflection or transmission of the probe light to produce optical
measurements of the probe light at the one or more different
optical wavelengths; and an authentication processor configured to
receive the fingerprint pattern authentication output from the
fingerprint pattern sensor and the optical measurements of the
probe light at the one or more different optical wavelengths from
the optical sensor module and to combine both the fingerprint
pattern authentication output and optical measurements of the probe
light to determine whether an access is to be granted or
denied.
29. The fingerprint detection module of claim 28, wherein: the
authentication processor is configured to combine the collected
fingerprint data from the fingerprint sensor chip and the detected
contact from the touch sensor to authenticate a person when the
collected fingerprint data matches stored fingerprint data of an
authorized user's fingerprint pattern and the detected contact
indicates the contact is from a live person, and to deny a person's
access when the collected fingerprint data matches stored
fingerprint data of an authorized user's fingerprint pattern while
the detected contact fails to indicate the contact is from a live
person.
30. A method for authenticating a request to access a locked mobile
device equipped with a fingerprint detection module, comprising:
obtaining measurements of (1) a contact provided by a person and
(2) a fingerprint input from the same person; determining whether
the detected contact provided by the person is from a live person;
comparing the fingerprint data from the obtained fingerprint input
against one or more stored fingerprint profiles associated with an
authorized user of the locked mobile device; and determining
granting or denying the person's access based on both of (1)
whether there is match in the fingerprint data and (2) whether the
detected contact indicates the contact is from a live person.
31. The method as in claim 30, wherein the access is granted when
there is match in the fingerprint data and (2) the detected contact
indicates the contact is from a live person.
32. The method as in claim 30, wherein the access is denied when
there is match in the fingerprint data and (2) the detected contact
fails to indicate the contact is from a live person.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent document claims the benefits and priorities of
U.S. Provisional Patent Application No. 61/908,026, filed on Nov.
22, 2013 and U.S. Provisional Patent Application No. 62/031,833,
filed on Jul. 31, 2014. The entire contents of the before-mentioned
patent applications are incorporated by reference as part of the
disclosure of this document.
TECHNICAL FIELD
[0002] The patent document relates to fingerprint recognition for
securely accessing a mobile device.
BACKGROUND
[0003] Electronic devices including portable or mobile computing
devices, such as laptops, tablets, smartphones, and gaming systems,
may employ user authentication mechanisms to protect personal data
and prevent unauthorized access. User authentication on an
electronic device may be carried out through one or multiple forms
of biometric identifiers, which can be used alone or in addition to
conventional password authentication methods. A popular form of
biometric identifiers is a person's fingerprint pattern. A
fingerprint sensor can be built into the electronic device to read
a user's fingerprint pattern so that the device can only be
unlocked by an authorized user of the device through authentication
of the authorized user's fingerprint pattern.
SUMMARY
[0004] Embodiments described in this document provide devices,
systems, and techniques that perform human fingerprint detection
and authentication for authenticating an access attempt to a locked
mobile device equipped with a fingerprint detection module. In one
aspect, a disclosed fingerprint detection system includes a touch
sensing module which includes a touch sensor (such as a metal ring)
and a sensor circuit for detecting an object making contact with
fingerprint detection system; an optical sensor module including
one or more light emitting sources and at least one photodetection
element, a fingerprint pattern sensor, and an authentication
processor. The touch sensing module is coupled to the optical
sensor module. If the touch sensing module detects an object, such
as a finger, the touch sensing module activates the optical sensor
module, which then produces probe light at two or more different
optical wavelengths to which a person's skin produces different
optical responses at the two or more different optical wavelengths
due to presence of blood in the person's skin. The optical sensor
module also includes an optical detection unit that receives a
reflection or transmission of the probe light to produce optical
measurements of the probe light at the two or more different
optical wavelengths. The optical measurements at different
wavelengths can then be used to compute values that are compared to
standard or calibrated values for human blood absorption to
determine if the object is human skin. The computation, comparison,
and determination operations can be performed by an on-chip signal
processing unit integrated with the optical sensor module.
[0005] Moreover, the optical sensor module is coupled to the
fingerprint pattern sensor. If the optical sensor module detects
human skin as the object making contact, the optical sensor module
activates the fingerprint pattern sensor, which includes a sensor
array for gathering fingerprint data and a fingerprint pattern
processor for determining whether the gathered fingerprint data
resembles a human fingerprint. The fingerprint pattern sensor is
coupled to an authentication processor. If the fingerprint pattern
sensor detects a human fingerprint, the fingerprint pattern sensor
activates the authentication processor. The authentication
processor receives the gathered fingerprint data from the
fingerprint pattern sensor and authenticates the gathered
fingerprint data against stored fingerprint data of an authorized
person's fingerprint pattern, and based on the verification outcome
to generate authorization output to either grant or deny the access
attempt.
[0006] In a high security operation mode, the authentication
processor can also receive the optical measurements at the two or
more optical wavelengths from the optical sensor module, and used
the optical measurements to detect a human heartbeat signal. This
heartbeat detection offers an additional check on whether a live
person is associated with the detected human fingerprint. The
authentication processor then generates an authorization decision
based on both the result of fingerprint authentication and the
result of heartbeat detection.
[0007] In one aspect, a technique for authenticating an access
attempt to a locked mobile device equipped with a fingerprint
detection module includes detecting whether an object is making
contact with the fingerprint detection module. When determined that
the object is making contact with the fingerprint detection module,
the technique can be used to determine whether the object is human
skin, and when determined that the object is human skin, the
techniques can be used to further determine whether the object
resembles human fingerprint associated with an access attempt. When
a human fingerprint is confirm, the technique can be used to gather
fingerprint data from the object; authenticate the gathered
fingerprint data against stored fingerprint profiles; and grant or
denying the access attempt based on the outcome of the gathered
fingerprint authentication.
[0008] In another aspect, a technique for authenticating an access
attempt to a locked mobile device equipped with a fingerprint
detection module includes, in response to detection of an object
making contact with the fingerprint detection module, determining
whether the object is human skin. When determined that the object
is human skin, the technique can be used to determine whether the
object resembles human fingerprint associated with an access
attempt. When human fingerprint is confirmed, the technique can be
used to gather fingerprint data from the object and authenticating
the gathered fingerprint data against stored fingerprint profiles.
When the gathered fingerprint data is authenticated as a valid
fingerprint, the technique can be used to determine whether the
object is associated with a heartbeat signal. When determined that
the object is associated with a heartbeat signal, the access
attempt is granted. Otherwise, the access attempt is denied.
[0009] In another aspect, a technique for authenticating an access
attempt to a locked mobile device equipped with a fingerprint
detection module includes detecting whether an object is making
contact with the fingerprint detection module. When determining
that the object is making contact with the fingerprint detection
module, the technique can be used to determine whether the object
is human skin. When determined that the object is human skin, the
technique can be used to gather fingerprint data from the object
and authenticate the gathered fingerprint data against stored
fingerprint profiles. When the gathered fingerprint data is
authenticated as a valid fingerprint, the technique can be used to
determine whether the object is associated with a heartbeat signal.
When determined that the object is associated with a heartbeat
signal, the access attempt is granted. Otherwise, the access
attempt is denied.
[0010] In yet another aspect, a fingerprint detection module
includes a substrate carrier and a fingerprint sensor chip located
on the substrate carrier for collecting fingerprint data. The
fingerprint detection module also includes a protective cover
placed over the fingerprint sensor chip to protect the fingerprint
sensor chip and a metal ring placed around the protective cover as
a touch sensor to detect if an object is making contact with the
fingerprint detection module. The fingerprint detection module
additionally includes an optical detection module that contains:
one or more light emitting sources located on the substrate carrier
and underneath the protective cover; at least one photodetection
element located on the substrate carrier and underneath the
protective cover; and a signal processing circuit integrated with
the fingerprint sensor chip. The fingerprint detection module
further includes a colored layer coated on the bottom surface of
the protective cover, wherein the colored layer contains
micro-holes in a first region directly above the one or more light
emitting sources and a second region directly above the at least
one photodetection element to allow light to pass through the
colored layer in the first region and the second region.
[0011] In yet another aspect, a fingerprint detection system
includes a touch sensor which contains a metal ring for detecting
an object making contact with the fingerprint detection module. The
fingerprint detection system also comprises a fingerprint pattern
sensor that includes a sensor array which reads a fingerprint
pattern and a fingerprint pattern processor that determines whether
the received fingerprint pattern matches stored information of an
authorized person's fingerprint pattern to provide a fingerprint
pattern authentication output. The fingerprint detection system
additionally includes an optical sensor module that produces probe
light at two or more different optical wavelengths to which a
person's skin produces different optical responses at the two or
more different optical wavelengths due to presence of blood in the
skin, the optical sensor module including an optical detection unit
that receives a reflection or transmission of the probe light to
produce optical measurements of the probe light at the two or more
different optical wavelengths. Moreover, the fingerprint detection
system includes an authentication processor that receives the
fingerprint pattern authentication output from the fingerprint
pattern sensor and the optical measurements of the probe light at
the two or more different optical wavelengths from the optical
sensor module and to combine both the fingerprint pattern
authentication output and optical measurements of the probe light
to determine whether an access is to be granted or denied.
[0012] Various examples of fingerprint detection modules and
fingerprint sensor modules described in this patent document can be
integrated with mobile devices (e.g., smartphones, tablets,
laptops), computing devices (e.g., personal computers), and other
electronic devices to perform fingerprint authentication processes
on these devices.
[0013] In yet another aspect, a method is provided for
authenticating a request to access a locked mobile device equipped
with a fingerprint detection module to include obtaining
measurements of (1) a contact provided by a person and (2) a
fingerprint input from the same person; determining whether the
detected contact provided by the person is from a live person;
comparing the fingerprint data from the obtained fingerprint input
against one or more stored fingerprint profiles associated with an
authorized user of the locked mobile device; and determining
granting or denying the person's access based on both of (1)
whether there is match in the fingerprint data and (2) whether the
detected contact indicates the contact is from a live person.
[0014] The above and other aspects of the disclosed technology and
their implementations and examples are described in greater detail
in the drawings, the description and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a schematic of a cross-sectional view of a
fingerprint detection module.
[0016] FIG. 2 shows a schematic of an exemplary fingerprint sensor
detector chip.
[0017] FIG. 3A shows a perspective and cross-sectional view of a
fingerprint detection module which includes an optical sensing
mechanism for determining whether a detected object is human.
[0018] FIG. 3B provides another perspective and cross-sectional
view of the fingerprint detection module in FIG. 3A.
[0019] FIG. 3C provides a perspective view of the entire
fingerprint detection module in FIG. 3A.
[0020] FIG. 4 illustrates the concept of using a fingerprint
detection module to detect and determine if a detected object is
human.
[0021] FIG. 5A shows a data plot of normalized human skin
reflectance (in %) as a function of wavelength of the light
source.
[0022] FIG. 5B shows a data plot of human blood light absorption
property (in extinction coefficient) as a function of the
wavelength of the light source.
[0023] FIG. 6A presents a flowchart illustrating a process of using
a fingerprint detection module to detect and determine if a
detected object is human.
[0024] FIG. 6B presents a flowchart illustrating a process of using
a fingerprint detection module having a metal ring circuit for
fingerprint detection and authentication.
[0025] FIG. 7 presents a diagram of a fingerprint detection module
for performing human fingerprint detection and authentication.
[0026] FIG. 8A shows a schematic of a mobile device integrated with
a touch panel and a fingerprint detection module.
[0027] FIG. 8B shows a schematic of another mobile device
integrated with a touch panel and a fingerprint detection
module.
[0028] FIG. 9A presents a flowchart illustrating a process of
activating a fingerprint detection module in standby mode and using
the fingerprint detection module to authenticate an access attempt
to a locked mobile device.
[0029] FIG. 9B presents a flowchart illustrating a process of
activating a fingerprint detection module in standby mode and using
the fingerprint detection module to authenticate an access attempt
to a locked mobile device in a highly secure mode.
[0030] FIG. 10 presents a flowchart illustrating a process of using
the fingerprint detection module to authenticate an access attempt
to a locked mobile device through a highly secure procedure.
[0031] FIG. 11A illustrates a fingerprint detection module as a
variation of fingerprint detection module for detecting and
determining whether a detected object is human.
[0032] FIG. 11B illustrates a fingerprint detection module which
includes a protective cover coated with a colored layer.
[0033] FIG. 12 presents a diagram of a fingerprint detection system
for performing human fingerprint detection and authentication.
[0034] FIG. 13A is a top-down view of an exemplary mobile device
showing a touch sensor assembly packaged under a display screen
cover glass.
[0035] FIG. 13B is a cross sectional view of the mobile device cut
along the line A-A.
[0036] FIG. 13C shows a cross-sectional view of the touch sensor
assembly shown in FIGS. 13A and 13B packaged to be under or flush
with the display screen cover glass 1310.
DETAILED DESCRIPTION
[0037] Electronic devices equipped with fingerprint authentication
mechanisms may be hacked by malicious individuals who can obtain
the authorized user's fingerprint, and copy the stolen fingerprint
pattern on a carrier object that resembles a human finger, which
can then be used to unlock the targeted device. Hence, the
fingerprint pattern, although a unique biometric identifier, may
not be by itself a completely reliable or secure identification.
The techniques, devices and systems described in this document
improve upon, or augment, a fingerprint authentication technology
used in electronic devices by providing an additional sensing
mechanism for determining whether the detected contact from the
object is from a live person to potentially prevent a stolen
fingerprint from being used to gain access to the targeted
device.
[0038] In some embodiments, a touch sensing module that includes a
touch sensor (e.g., implemented using a metal ring or other similar
conductive materials and structures) placed around a fingerprint
detection module on a mobile device and associated touch sensing
circuitry communicatively coupled to the touch sensor can be used
to detect a contact from an object with the touch sensor, such as
the metal ring and the fingerprint detection module. The touch
sensing module can be used to activate the fingerprint detection
module and the mobile device in a power saving/standby mode with a
light touch, without additional user input such as actuating a
mechanical switch or button. However, in everyday uses when a user
is holding or carrying (e.g., in a pocket close to the body) a
mobile device, unintended and incidental contact the touch sensing
module are common and can be difficult to avoid. It can be
undesirable from power saving perspective if any contact by a
finger or a part of the human body with the touch sensing module
indiscriminately activates the fingerprint detection module and/or
the mobile device in power saving/standby mode. Embodiments
described in this document provide devices, systems, and techniques
that enable light touch activations of fingerprint detection module
while preventing or reducing unintended and incidental touches from
activating the fingerprint detection module and/or the mobile
device in a standby mode.
[0039] Embodiments described in this document provide devices,
systems, and techniques that perform human fingerprint detection
and authentication for authenticating a user requesting to gain
access to a locked mobile device equipped with a fingerprint
detection module. In one aspect, a fingerprint detection system
includes a touch sensing module which includes a touch sensor (such
as a metal ring) and a sensor circuitry for detecting an object
making contact with the fingerprint detection system; an optical
sensor module, a fingerprint pattern sensor, and an authentication
processor. The touch sensing module is communicatively coupled to
the optical sensor module. Responsive to the touch sensing module
detecting a contact from an object, such as a finger, the touch
sensing module activates the optical sensor module, which then
produces probe light signals at two or more different optical
wavelengths to which a person's skin produces different optical
responses at the two or more different optical wavelengths due to
presence of blood in the person's skin. The optical sensor module
includes an optical detection unit that receives a reflection or
transmission of the probe light signals to produce optical
measurements of the probe light signals at the two or more
different optical wavelengths. The optical measurements at
different wavelengths can then be used to compute values that are
compared to standard or calibrated values for human blood
absorption to determine whether the detected contact from the
object is from human skin. The computation, comparison, and
determination operations can be performed by an on-chip signal
processing unit integrated with the optical sensor module.
[0040] Moreover, the optical sensor module is coupled to the
fingerprint pattern sensor. Responsive to the optical sensor module
detecting that the contact is from human skin, the optical sensor
module activates the fingerprint pattern sensor, which includes a
sensor array for gathering fingerprint data and a fingerprint
pattern processor for determining whether the gathered fingerprint
data resembles a human fingerprint. The fingerprint pattern sensor
is communicatively coupled to an authentication processor.
Responsive to the fingerprint pattern sensor detecting a human
fingerprint of a user requesting access to the locked mobile
device, the fingerprint pattern sensor activates the authentication
processor. The authentication processor receives the gathered
fingerprint data from the fingerprint pattern sensor and attempts
to authenticate the user by comparing the gathered fingerprint data
against stored fingerprint data of an authorized user's fingerprint
pattern. Based on the result of the attempted authentication, the
authentication processor can generate an authorization decision to
either grant or deny access to the locked mobile device.
[0041] In a high security operation mode, the authentication
processor can also receive optical measurements at two or more
optical wavelengths from the optical sensor module, and use the
received optical measurements to detect a human heartbeat signal.
The optical heartbeat detection can potentially offer an additional
verification on whether a live user is associated with the detected
human fingerprint. The authentication processor then generates an
authorization decision based on both the result of the fingerprint
comparison and the result of optical heartbeat detection.
[0042] In one aspect, a technique for authenticating a user
requesting to gain access to a locked mobile device equipped with a
fingerprint detection module includes detecting a contact from an
object on the fingerprint detection module. Responsive to
determining that the detected contact from the object is from human
skin, the technique can be further used to determine whether the
detected contact from human skin resembles contact from a human
fingerprint associated with a user requesting to access the locked
mobile device. Responsive to determining that the detected contact
is from a human fingerprint, the technique can be used to obtain
fingerprint data from the human skin. The obtained fingerprint data
can be compared against stored fingerprint profiles in an attempt
to authenticate the user, and user access to the locked mobile
device can be granted when the obtained fingerprint matches one of
the stored fingerprint profiles associated with an authorized user
of the locked mobile device.
[0043] In another aspect, a technique for authenticating a user
requesting access to a locked mobile device equipped with a
fingerprint detection module includes, in response to detecting a
contact from an object with the fingerprint detection module,
determining whether the detected contact from the object is from
human skin. Responsive to detecting the contact from human skin,
the technique can be used to determine whether the detected contact
from human skin resembles contact from human fingerprint associated
with a user requesting an access to the locked mobile device.
Responsive to determining that the contact is from human
fingerprint, the technique can be used to obtain fingerprint data
from the human fingerprint and attempt to authenticate the user by
comparing the obtained fingerprint data against stored fingerprint
profiles of an authorized user. Responsive to matching the obtained
fingerprint data with stored fingerprint profiles of an authorized
user, the technique can be used to subsequently determine whether
the detected object is associated with a heartbeat signal.
Responsive to associating a heartbeat with the detected object,
user access is granted. Otherwise, the access attempt is
denied.
[0044] In another aspect, a technique for authenticating a user
requesting access to a locked mobile device equipped with a
fingerprint detection module includes detecting a contact from an
object with the fingerprint detection module. Responsive to
detecting the contact, the technique can be used to determine
whether the contact from the object is from human skin. Responsive
to detecting contact from human skin, the technique can be used to
obtain fingerprint data from the human skin and compare the
obtained fingerprint data against stored fingerprint profiles of an
authorized user. Responsive to finding a match between the obtained
fingerprint data and the stored fingerprint profiles of an
authorized user, the obtained fingerprint is identified as a valid
fingerprint of an authorized user. The technique can be used to
subsequently determine whether the object making contact is
associated with a heartbeat signal. Responsive to detecting a heart
beat signal from the human skin having a fingerprint, the user
access is granted. In absence of both fingerprint detection and
heartbeat detection, the user access attempt is denied.
[0045] In yet another aspect, a fingerprint detection module
includes a substrate carrier and a fingerprint sensor chip located
on the substrate carrier for collecting fingerprint data. The
fingerprint detection module also includes a protective cover
placed over the fingerprint sensor chip to protect the fingerprint
sensor chip and a touch sensor placed around the protective cover
to detect a contact from an object with the fingerprint detection
module. The touch sensor can be made of a conductive material that
borders at or near an outline of the protective cover and can be
shaped to conform with the outline of the protective cover. For a
round protective cover, the touch sensor can be a metal ring for
example. For a rectangular protective cover, the touch sensor can
be a metal rectangular frame for another example. Also, the
fingerprint detection module includes an optical detection module
that contains: one or more light emitting sources located on the
substrate carrier and underneath the protective cover; at least one
photodetection element located on the substrate carrier and
underneath the protective cover; and a signal processing circuit
integrated with the fingerprint sensor chip. In addition, the
fingerprint detection module includes a colored layer coated on the
bottom surface of the protective cover. The colored layer contains
micro-holes in a first region directly above the one or more light
emitting sources and a second region directly above the at least
one photodetection element to allow light to pass through the
colored layer in the first region and the second region.
[0046] In yet another aspect, a fingerprint detection system
includes a touch sensor such as a metal ring to detect a contact
from an object with the fingerprint detection module. Also, the
fingerprint detection system includes a fingerprint pattern sensor
to detect a fingerprint pattern. The fingerprint patter sensor can
be implemented using a sensor array, for example. The fingerprint
detection system can include a fingerprint pattern processor to
determine whether the detected fingerprint pattern matches stored
information of an authorized person's fingerprint pattern to
provide a fingerprint pattern authentication output. Also, the
fingerprint detection system includes an optical sensor module to
produce probe light signals at two or more different optical
wavelengths to which a user's skin produces different optical
responses at the two or more different optical wavelengths due to
the presence of blood in the skin. The optical sensor module
includes an optical detection unit to receive a reflection or
transmission of the probe light signals to produce optical
measurements of the probe light signals at the two or more
different optical wavelengths. Moreover, the fingerprint detection
system includes an authentication processor to receive the
fingerprint pattern authentication output from the fingerprint
pattern sensor and the optical measurements of the probe light
signals at the two or more different optical wavelengths from the
optical sensor module. The fingerprint detection system can combine
both the fingerprint pattern authentication output and optical
measurements of the probe light signals to determine whether an
access is to be granted or denied.
[0047] Embodiments described in this document provide devices,
systems, and techniques that implement various fingerprint
detection modules for human fingerprint detection and
authentication. Moreover, embodiments described in this document
provide devices, systems, and techniques that implement various
fingerprint detection modules including an optical sensing unit to
determine if a detected object is human. Specifically, the
technology disclosed in this document uses an additional
measurement or sensing mechanism to make another measurement beyond
the fingerprint sensing obtained from a person to combine with
detection of the person's fingerprint pattern as a combination
authentication method to identify whether the authorized person is
accessing the device.
[0048] The disclosed technology uses probe light at two or more
different probe light wavelengths in the additional sensing
mechanism where the human skin provides different optical responses
at the two or more different wavelengths. Measurements of such
optical responses at the two or more different wavelengths are used
to combine with the positive identification of the person's
fingerprint pattern to authenticate the access. This additional
layer of authentication can improve the level of authentication and
the security that may not be possible by using the fingerprint
pattern alone. In the specific examples described below, the two or
more different probe light wavelengths may be selected so that
reflectance or absorption of the person's skins due to presence of
the blood in the skin and the oxygen level in the blood to cause
different optical responses in the reflected light or transmitted
light at the selected two or more different wavelengths. In
implementation, the device can include two sensor devices: (1) a
fingerprint pattern recognition sensor and (2) an optical detection
module for producing probe light of two or more different
wavelengths and for measuring the reflectance or transmission of
the probe light of the finger to measure the optical responses of
the finger at the two or more different wavelengths. The
measurements from the two sensor devices are combined to
authenticate a person for accessing the device. In implementations,
those two sensor devices can be integrated into a fingerprint ID
module located on a surface of a device to enable a user to input
the user's fingerprint when accessing the device. The appearance of
such a fingerprint ID module may be similar to other fingerprint ID
modules where only fingerprint patterns are detected and processed
but the additional optical detection module based the measurements
of probe light of two or more different wavelengths provides a
unique added security and accuracy in granting proper user access
to the device.
[0049] FIG. 1 shows a schematic of a cross-sectional view of a
fingerprint detection module 100 (finger is not included). As shown
in FIG. 1, fingerprint detection module 100 includes a substrate
carrier 102 and a fingerprint sensor detector chip 104 affixed on
top of substrate carrier 102. Fingerprint sensor detector chip 104
can use capacitive sensing to collect fingerprint data and detect
fingerprints. However, fingerprint sensor detector chip 104 can
also be configured to collect fingerprint data and detect
fingerprints by non-capacitive means. Fingerprint detection module
100 also includes a protective cover 106 which is placed over
fingerprint sensor detector chip 104 to protect fingerprint sensor
detector chip 104 and can also serve as a dielectric spacer.
Protective cover 106 may be made out of high dielectric-constant
material, such as ceramic, sapphire, zirconia, among others.
Protective cover 106 may also have a hard coating, such as diamond
like carbon. Note that in the embodiment of FIG. 1, the edges of
protective cover 106 extends beyond the edges of fingerprint sensor
detector chip 104 in all directions.
[0050] Fingerprint detection module 100 additional includes a metal
ring 108 placed on substrate carrier 102 and around protective
cover 106, which protects the edge of protective cover 106 and can
also serve as a signal electrode. Note also that a finger 110 (not
part of fingerprint detection module 100) can make contact with
metal ring 108 when finger 110 is pressed on fingerprint detection
module 100 for fingerprint detection.
[0051] FIG. 2 shows a schematic of an exemplary fingerprint sensor
detector chip 200. Note that fingerprint sensor detector chip 200
(or "sensor chip 200") may be used as sensor chip 104 in
fingerprint detection module 100 or in combination with other types
of fingerprint detection modules described below.
[0052] As shown in FIG. 2, fingerprint sensor detector chip 200
comprises a pixelated sensing element array 202 which occupies a
significant portion of the sensor chip. Each sensing element in
pixelated sensing element array 202 may be a CMOS capacitive sensor
or other types of sensors capable of sensing fingerprint features.
Fingerprint sensor detector can also include a signal processing
unit 204 for processing signals received from pixelated sensing
element array 202, and a connection unit 206 coupled to signal
processing unit 204. Connection unit 206 may include multiple
electrodes which can be connected to external circuitry through
wire-bonding, bump bonding or other connection means. Connection
unit 206 may be situated along an edge of sensor chip 200 for the
convenience of interfacing with other components of a fingerprint
detection module.
[0053] Note that sensor chip 200 also includes one or more
photodetection elements 208, which may be located at one or more
sections of sensor chip 200. Photodetection elements 208 can
include, but are not limited to CMOS photodetectors, charge-coupled
devices (CCD) photodetectors, light-emitting diode (LED)
photodetectors, photoresistors, photovoltaic photodetectors, and
photodiodes. In the embodiment shown, there are two photodetection
elements located along one edge section of the sensor chip. In one
embodiments, there can be just a single photodetection element or
more than two photodetection elements. The multiple photodetection
elements may be located at different edge sections of the silicon
chip instead of all on the same side of the chip. Note that while
FIG. 2 shows that photodetection elements 208 are integrated with
pixelated sensing element array 202 on the same chip, other
embodiments can have the photodetection elements off the sensor
chip on a different area of the fingerprint sensor module.
[0054] FIG. 3A shows a perspective and cross-sectional view of a
fingerprint detection module 300 which includes an optical sensing
mechanism for determining whether a detected object is human.
Similarly to fingerprint detection module 100, fingerprint
detection module 300 includes a substrate carrier 302, a
fingerprint sensor detector chip 304, a protective cover 306, and a
metal ring 308. Fingerprint sensor detector chip 304 can be
fingerprint sensor detector chip 200 to include one or more
photodetection elements. In some embodiments however, the one or
more photodetection elements are located off of sensor chip 200 and
on another area of substrate carrier 302 cavity protective cover
306. The protective cover can be made of transparent materials,
such as sapphire or zirconia. If there are cosmetic coloring
applied to protective cover 306, a transparent window may be used
on protective cover 306 to allow light to go through. Note that in
this embodiment, protective cover 306 covers the entire surfaces of
sensor chip 304.
[0055] Fingerprint detection module 300 also includes one or more
light emitting sources 310 which can be placed within a cavity 312
of metal ring 308. Light emitting sources 310 can include one or
more light emitting diode (LED) chips, one or more diode lasers, or
one or more other miniature light emitting devices. An exemplary
LED chip in such applications can have an area of .about.200
.mu.m.times.200 .mu.m and a thickness of .about.200 .mu.m. In the
embodiment shown, cavity 312 has a ring structure which is formed
around the underside of metal ring 308. However, cavity 312 in
metal ring 308 can have many other configurations, for example, to
only present around the locations of light emitting sources
310.
[0056] Light emitting sources 310 can be configured to emit
detection light of desirable wavelengths in response to a human
finger or an object making contact with fingerprint detection
module 300. For example, metal ring 308 can serve as a sensing
electrode to detect the contact from a human finger or an object.
Light emitting sources 310 can emit light through one or more light
emitting windows which cut through metal ring 308 to connect to
cavity 312. In FIG. 3A, a light emitting window 314 is located
directly above one of the light emitting sources 310 inside cavity
312. In some embodiments, light emitting sources 310 include an
modulated light source.
[0057] FIG. 3B provides another perspective and cross-sectional
view of fingerprint detection module 300. FIG. 3C provides a
perspective view of entire fingerprint detection module 300.
[0058] FIG. 4 illustrates the concept of using a fingerprint
detection module 400 (which is substantially similar to fingerprint
detection module 300) to detect and determine where a detected
object is human. While FIG. 4 is described in the context of
fingerprint detection module 400, the techniques described are
general applicable to many variations of fingerprint detection
module 400, some of which will be described later in the
disclosure.
[0059] As mentioned above, fingerprint detection module 400
includes substrate carrier 402, protective layer 406, metal ring
408 and sensor chip 404, which may include a capacitive sense array
for sensing a fingerprint's ridge and valley patterns. Fingerprint
detection module 400 includes light emitting sources 410 which
reside within a cavity under metal ring 408. In some
implementations, light emitting sources 410 can emit at least two
different wavelengths through light emitting window 414 of metal
ring 408. Fingerprint detection module 400 also includes one or
more photodetectors 416 which can either be integrated on sensor
chip 404 or separately placed on substrate carrier 402. In the
embodiment shown, photodetectors 416 are located on an edge of
sensor chip 404.
[0060] In some implementations, when an object 420 (not part of
fingerprint detection module 400) makes contact of fingerprint
detection module 400, light emitting sources 410 emits detection
light through light emitting window 414. The detection light is
reflected off object 420 and the reflected light can be received
and measured by photodetectors 416. In particular implementations,
one or more wavelengths of detection light are emitted by light
emitting sources 410. For heartbeat detection, one wavelength of
detection light is sufficient. For detecting touch from actual
human fingerprint, while one wavelength of detection light is
enough, two or more wavelengths can be beneficial. For example, for
one wavelength, the wavelength selected can be 660 nm. For two or
more wavelengths, one wavelength selected can be 660 nm and the
other wavelength can be one of 905 nm, 910 nm or 940 nm. In another
embodiments, the two wavelengths selected can be 590 nm and 805 nm
respectively. In yet another embodiments, the two wavelengths
selected can be 520 nm and 575 nm. In some embodiments, only one
wavelength is needed and any one of the above identified
wavelengths or other wavelengths appropriate for the application
(e.g., heartbeat detection) can be used.
[0061] FIG. 5A shows a data plot of normalized human skin
reflectance (in %) as a function of the wavelength of the light
source. Note that human skin has different reflectance in response
to different wavelengths and this relationship can be measured. As
a result, the photodetector signals corresponding to the reflected
light from the two selected wavelengths can be significantly
different. In some implementations, photodetectors 416 can be
configured to measure the reflected light from both wavelengths.
The ratio of the two measurements can then be computed and compared
to a standard or calibrated value for human finger/skin to
determine if object 420 is human finger or not. The computation,
comparison, and determination operations can be performed by an
on-chip signal processing unit such as signal processing unit 204
shown in FIG. 2.
[0062] FIG. 5B shows a data plot of human blood light absorption
property (in extinction coefficient) as a function of the
wavelength of the light source. Note that human blood has different
absorptions in response to different wavelengths. Moreover, for
blood Hemoglobin lack of Oxygen (referred to as "Hb state") and
bound with Oxygen (referred to as "HbO2 state"), the absorption
behaviors are also significantly different. As a result, the
photodetector signals corresponding to the reflected light from the
two selected wavelengths can be significantly different, and the
photodetector signals corresponding to the reflected light from the
same wavelength under Hb or HbO2 state can also be significantly
different. In some implementations, photodetectors 416 can be
configured to measure the transmitted light through object 420 for
both wavelengths. The ratio of the two measurements can then be
computed and compared to a standard or calibrated value for human
blood absorption to determine if object 420 is human finger or not.
The computation, comparison, and determination operations can be
performed by an on-chip signal processing unit such as signal
processing unit 204 shown in FIG. 2.
[0063] Photodetectors 416 can also be configured to measure the
transmitted light through object 420 for one or both wavelengths
under both Hb state and HbO2 state. The ratio of the two
measurements at two different wavelengths in each of the two states
can then be computed and compared to standard or calibrated values
for human blood absorption to determine if object 420 is human
finger or not. The computation, comparison, and determination
operations can be performed by an on-chip signal processing unit
such as signal processing unit 204 shown in FIG. 2.
[0064] The above measurements in FIG. 5A or 5B or both at the two
different optical wavelengths can also be used to measure the
person's heartbeat based on the oxygen level in the blood due to
pumping by the heart. The two different wavelengths can be at the
red spectral range and the infrared spectral range, respectively.
The heartbeat measurement is used in some pulse oximeter devices or
heart rate monitors based on measurements of the saturated level of
oxygen in the blood. The relative absorption of red (absorbed by
oxygenated blood) and infrared (absorbed by deoxygenated blood)
light correlates to arterial blood oxygen saturations. Measurements
of relative light absorption are made and are processed to generate
the heart beat rate. This heart beat measurement provides another
check on whether the person is present when the fingerprint pattern
is presented to the target device that is to be accessed.
[0065] As mentioned above, a touch sensor within the fingerprint
detection module, such as metal ring 408 in fingerprint detection
module 400 can be used to detect the initial contact of an object,
such as a user's finger. In one embodiment, the metal ring may be
part of circuitry for initial contact detection and module
activation. In some embodiments, the fingerprint detection module
can be in a standby mode (i.e., power saving mode) before the
detection of a new contact. Upon detecting a new contact, the metal
ring circuitry then activates the main circuit of the fingerprint
detection module. When a current fingerprint detection and
authentication process is complete, the main circuitry of the
fingerprint detection module can be turned off or deactivated and
the fingerprint detection module returns to the standby mode while
the metal ring circuitry remains active and ready for next
contact.
[0066] FIG. 6A presents a flowchart illustrating a process 600 of
using a fingerprint detection module to detect and determine if a
detected object is human. The process 600 may be understood in the
context of fingerprint detection module 400. The process may begin
when the fingerprint detection module detects an object is making
contact with the fingerprint detection module (602). In one
embodiment, the metal ring within the fingerprint detection module
and associated circuit (e.g., metal ring 408 in module 400) may be
used for the contact detection. Note that light emitting sources
within the fingerprint detection module may be in off mode at this
point and may be activated by the detection of the contact. Light
emitting sources within the fingerprint detection module start to
emit detection light of two selected wavelengths in response to the
detection of contacting object (604). The one or more
photodetectors within the fingerprint detection module measure
light signals which can include a portion of the detection light
reflected off of the contacting object and/or a portion of the
detection light passing through (i.e., transmitted light) the
contacting object (606). Note that the portion of the detection
light passing through the contacting object can be used to
determine a light absorption property of the contacting object. A
signal processing module processes the photodetector signals
corresponding to the two selected wavelengths, and determines
whether the detected object is human by comparing the computed
signal ratios of the two selected wavelengths with the
characteristic values of the same parameters of a human finger
(608). When the detection and authentication process is complete,
the light emitting sources may be turned off to save power
(610).
[0067] As mentioned above, a metal ring within the fingerprint
detection module, such as metal ring 408 in fingerprint detection
module 400 can be used to detect the initial contact of a finger or
an object. In one embodiment, the metal ring may be part of a
circuit for initial contact detection and module activation. In
some embodiments, the fingerprint detection module can be in a
standby mode (i.e., power saving mode) before the detection of a
new contact. Upon detecting a new contact, the metal ring circuit
then activates the main circuit of the fingerprint detection
module. When a current fingerprint detection and authentication
process is complete, the main circuit of the fingerprint detection
module can be turned off or deactivated and the fingerprint
detection module returns to the standby mode while the metal ring
circuit remains active and ready for next contact.
[0068] FIG. 6B presents a flowchart illustrating a process 620 of
using a fingerprint detection module (e.g., fingerprint detection
module 400) having a metal ring circuit for fingerprint detection
and authentication in accordance with some embodiments described in
this patent document. Before the process begins, the main
fingerprint sensor and the associated circuits (which can include
the fingerprint sensor chip, and/or the light emitting sources and
the photodetectors) of the fingerprint detection module are in
standby mode (i.e., power saving mode), and only a metal ring
circuit is functional or active. Note that the metal ring circuit
includes both the metal ring as a sensor and an associated circuit
coupled to the metal ring to generate a detection signal when an
object makes contact with the metal ring. The process begins when
the fingerprint detection module detects that an object is making
contact with the fingerprint detection module based on a detection
signal produced by the metal ring circuit (622). Next, the
fingerprint detection module activates the main fingerprint sensor
and associated circuits, and gathers fingerprint sensor data (e.g.,
by scanning the object) (614). Fingerprint detection module then
processes the collected fingerprint sensor data to confirm the
fingerprint is detected (616). When the fingerprint detection
module cannot confirm the fingerprint data at the process at 616,
fingerprint detection module may continue to gather fingerprint
sensor data. The fingerprint detection module performs image
processing on the gathered fingerprint data to verify whether the
fingerprint data match the register fingerprint and either
authorizes or denies access (618). After authentication process is
complete, the fingerprint detection module is switched to standby
mode to save power, while the metal ring circuit remains active
(620).
[0069] FIG. 7 presents a data flow diagram of an exemplary
fingerprint detection module 700 for performing human fingerprint
detection and authentication in accordance with some embodiments
described in this patent document. As shown in FIG. 7, fingerprint
detection module 700 includes a fingerprint pattern sensor 702 and
an optical sensor module 704, both of which are coupled to an
authentication processor 706. Fingerprint pattern sensor 702
includes a sensor array which reads a fingerprint pattern and a
fingerprint pattern processor in communication with the sensor
array to determine whether the fingerprint pattern read by the
sensor array matches stored information of an authorized person's
fingerprint pattern to provide a fingerprint pattern authentication
output 708. Optical sensor module 704 produces probe light at one
or more optical wavelengths to which a person's skin produces
different optical responses at the one or more optical wavelengths
due to presence of blood in the person's skin. Optical sensor
module 704 also includes an optical detection unit that receives a
reflection or transmission of the probe light to produce data
indicative of optical measurements 710 of the probe light at the
one or more optical wavelengths. The produced data indicative of
optical measurements 710 are provided to the authentication
processor 706. The authentication processor 706 receives the
fingerprint pattern authentication output 708 from fingerprint
pattern sensor 702 and the optical measurements 710 data of the
probe light at the one or more optical wavelengths from optical
sensor module 704 and to combine both fingerprint pattern
authentication output 708 and optical measurements 710 of the probe
light to produce an authentication output 712 which can be used to
determine whether an access is to be granted or denied.
[0070] FIG. 8A is a schematic showing a cross sectional view of an
exemplary mobile device 800 integrated with a touch screen assembly
and a fingerprint detection module. As shown in FIG. 8A, mobile
device 800 (e.g., a smartphone) includes a fingerprint detection
module 802 having a touch sensor such as a metal ring 804
positioned to be substantially level with a surface of mobile
device 800 parallel with a surface of top cover glass 806 exposed
to the user. The touch sensor can be implemented using any
conductive material, such as any number of known metals. In
addition, the shape of the touch sensor can vary based on the shape
and design of the fingerprint detection module. The touch sensor
can be designed to border at or near the outline of the fingerprint
detection module so as to substantially surround the portion of the
fingerprint detection module exposed to a user. For example, for a
fingerprint detection module in a round shape, a metal ring can be
used as the touch sensor. For a fingerprint detection module shaped
as a rectangle, the touch sensor can be formed in the shape of a
rectangular frame. The top cover glass 806 of mobile device 800
includes an opening to allow fingerprint detection module 802 to
fit through and be exposed on the surface. In addition, top glass
806 can be implemented using transparent materials other than glass
including various crystalline structures, such as sapphire that
provides the mobile device 800 with protection while allowing at
least visible light to pass through. Mobile device 800 also
includes a touch panel 808 and an LCD display module 810 positioned
underneath capacitive touch panel 808. Touch panel 808 can be
implemented using various touch technologies including a capacitive
touch sensor, an inductive touch sensor, and other touch sensors.
The touch panel and the LCD display module 810 together form the
touch screen assembly. When mobile device 800 is locked, LCD
display module 810 is turned off and a main processor of mobile
device 800 and fingerprint detection module 802 are in standby
mode. To unlock mobile device 800, a user can make contact with the
fingerprint detection module 802 with the user's finger, for
example. A touch sensor such as metal ring 804 and associated
circuitry communicatively coupled to the metal ring 804 can be used
to detect a contact from an object 812 with the fingerprint
detection module 802. The touch sensor and associated circuitry can
be used to activate fingerprint detection module 802 responsive to
a light contact, without additional user input through a mechanical
switch, such as actuating a physical button.
[0071] FIG. 8B is a schematic showing a cross sectional view of
another exemplary mobile device 820 integrated with a touch screen
assembly and a fingerprint detection module. Similar to mobile
device 800 in FIG. 8A, mobile device 820 includes a fingerprint
detection module 822 having a touch sensor, such as a metal ring
824. However, different from mobile device 800, the top cover glass
826 of mobile device 820 does not have an opening to expose the top
surface (e.g., the surface exposed to the user) of fingerprint
detection module 822. Instead, fingerprint detection module 822 is
positioned underneath top cover glass 826 and is designed to sense
a fingerprint of a finger without being directly in contact with
the finger 832.
[0072] In the embodiment of FIG. 8B, top cover glass 826 protects
touch panel 828 and LCD display module 830 of the touch screen
assembly and other areas of a top surface of mobile device 820
substantially parallel with the top cover glass 826 beyond the
touch sensitive area associated with the touch panel, including a
location above fingerprint detection module 822. Touch panel 828 is
embedded within a support glass 834 underneath top cover glass 826.
Top cover glass 826 and support glass 834 can be implemented using
materials similar to top cover glass 806. Support glass 834
includes an opening to allow fingerprint detection module 822 to
pass through and be placed under the top cover glass 826. The
location of the opening in support glass 834 may be closer to one
end of support glass 834, similar to the relative location of the
opening in top cover glass 806 in FIG. 8A. The fingerprint
detection module 822 in this design can sense a contact from a
fingerprint of a finger 832 with a top surface (e.g., the surface
exposed to the user) of the hardened top cover glass 826 without
having an object such as the finger 832 being in direct contact
with a surface on the fingerprint detection module 822. This allows
top cover glass 826 to fully cover both the touch screen assembly
and the fingerprint sensor under a spatially contiguous protective
surface without an opening.
[0073] In one embodiment, top cover glass 826 and support glass 834
are bonded together to form an overall cover glass structure that
is significantly thicker and mechanically stronger than each of top
cover glass 826 and support glass 834 individually. The two glass
layers may be bonded with a thin adhesive layer, such as an epoxy
adhesive layer. The overall thickness of the combined structure may
be comparable to top cover glass 806 in FIG. 8A. Fingerprint
detection module 822 which is positioned within the opening of
support glass 834 may be directly attached underneath top cover
glass 826.
[0074] In everyday uses when a user is holding or carrying mobile
device 800 or mobile device 820 (e.g., in a pocket close to the
body), unintended and incidental contacts on metal ring 804 or an
surface area directly above metal ring 824 are common and can be
difficult to avoid. Activation of fingerprint detection module 802
or 822 and/or the main processor of mobile device 800 or 820 from a
standby mode due to unintended contacts with the touch sensor can
negatively impact power consumption of a mobile device. Devices,
systems, and techniques described in various embodiments of this
document can potentially enable light contact activation of
fingerprint detection module 802 or 822 while preventing unintended
contacts from activating the same fingerprint detection module 802
or 822 and/or mobile device 800 or 820 from a standby mode.
[0075] FIG. 9A presents a flowchart illustrating an exemplary
process 900 of activating a fingerprint detection module from
standby mode and using the fingerprint detection module to
authenticate a user's request to gain access to a locked mobile
device. The exemplary process 900 of FIG. 9A is described with
respect to fingerprint detection module 400 and mobile device 800
or 820. A fingerprint detection module (e.g., fingerprint detection
module 400) in standby mode has a touch sensor enabled to
continuously receive from the touch sensor a touch sensor signal
(e.g., a metal ring signal from the metal ring touch sensor)
indicating a contact from an object with the touch sensor (e.g.,
metal ring) and the fingerprint detection module (902). In one
embodiment, the metal ring touch sensor (e.g., metal ring 408 in
module 400) of the fingerprint detection module and associated
touch sensing circuitry (which may be integrated with sensor chip
404) are used for the contact detection. For example, the
associated touch sensing circuitry can generate a signal in
response to an increase of capacitive load on the metal ring caused
by an object, such as a finger, making contact with the metal ring.
Note that light emitting sources within the fingerprint detection
module are not enabled at this point. Until a metal ring signal is
detected at 902, the fingerprint detection module stays in standby
mode waiting for the metal ring signal indicating a detected
contact as shown in FIG. 9A.
[0076] Responsive to the fingerprint detection module receiving a
metal ring signal from the touch sensor and associated touch
sensing circuitry, the fingerprint detection module activates an
optical detection module and turns on light emitting sources, such
as LEDs within the fingerprint detection module to emit detection
light of two selected wavelengths (904). The optical detection
module includes one or more photodetectors within the fingerprint
detection module (e.g., photodetector 416 in module 400) to measure
optical signals associated with the emitted detection light
reflecting off of the contacting object and/or the emitted
detection light passing through (i.e., transmitted light) the
contacting object (906). The detection light passing through the
contacting object can be used to determine a light absorption
property of the contacting object. A signal processing module
processes photodetector signals corresponding to the measured
optical signals in two predetermined wavelengths. Based at least
partially on the processed photodetector signals, the signal
processing module determines whether the detected contact is from
human skin by comparing computed signal ratios of the processed
photodetector signals at two selected wavelengths with the
characteristic values of the same parameters of human skin (908).
In some implementations, the optical detection module is integrated
with the fingerprint sensor chip.
[0077] When the determination at 908 is that the detected contact
is not from human skin, the fingerprint detection module is
switched back to the standby mode (902). For example, the detected
contact could be based on a non-human-skin object making contact
with the metal ring, such as human body touching the metal ring
through clothing. In one implementation, returning to the standby
mode also involves turning off the light emitting sources. However,
when the determination at 908 is that the detected contact is from
human skin, the fingerprint detection module activates the main
fingerprint sensor and the associated circuitry in the fingerprint
detection module, and begins obtaining fingerprint sensor data from
the human skin (910).
[0078] The fingerprint detection module processes the obtained
fingerprint sensor data to determine whether a human fingerprint is
detected (912). This is performed prior to full fingerprint
verification to distinguish a human fingerprint from another part
of human skin, such as another part of a human hand, human arm, and
human face, making contact with the fingerprint detection module.
In some implementations, the initial determination of human
fingerprint at 912 does not obtain and process the full fingerprint
data in order to save power and processing time. For example, the
fingerprint sensor measures one-directional (1D) human skin profile
and associated detection circuitry determines whether the measured
1D skin profile substantially matches a human fingerprint. The
detection circuitry associated with the fingerprint sensor can
compare the measured 1D skin profile with a typically 1D
fingerprint contour that includes a periodic ridge and valley
pattern and determine whether the measured 1D skin profile
resembles a human fingerprint. Moreover, the detection circuitry
used to perform the initial determination of human fingerprint at
912 can be low power detection circuitry within the fingerprint
detection module, for example, circuitry integrated with the sensor
chip. As such, performing the initial determination of human
fingerprint at 912 does not require the main processor (e.g., the
application processor) of the mobile device, which can remain in
standby mode until full fingerprint verification is needed. Using
partial fingerprint data and low power circuitry can ensure low
power consumption at 910 and 912.
[0079] When the determination at 912 is that a human fingerprint is
not detected from the human skin, the fingerprint detection module
again is switched back to the standby mode at 902. For example, the
detected contact from human skin without a human fingerprint can be
the result of a contact from a side of the user's hand, arm or face
with the metal ring. In one implementation, returning to the
standby mode of 902 also includes turning off the light emitting
sources.
[0080] When the determination at 912 is that the detected contact
is from a human fingerprint, the fingerprint detection module then
obtains full fingerprint data with the fingerprint sensor and sends
the obtained full fingerprint data to the main processing unit for
processing (914), which may involve waking up the main processing
unit from the standby mode. The full fingerprint sensor data is
processed by the main processing unit to verify whether the
obtained full fingerprint data match the stored fingerprint data of
an authorized user of the mobile device. Based on the outcome of
the verification, the main processing unit authorizes or denies
user access to the locked mobile device (916). The fingerprint
detection module is switched back to the standby mode at 902 if
access is denied. Otherwise, if the access is granted, the
fingerprint detection module is also switched back to the standby
mode but does not return back to 902.
[0081] FIG. 9B presents a flowchart illustrating an exemplary
process 901 of authenticating user request to access a locked
mobile device in a high security mode based on a combination of
fingerprint detection and optical heartbeat detection. The process
901 illustrated in FIG. 9B includes a fingerprint detection process
which is substantially similar to the process 900 of FIG. 9A from
(902) to (914). The full fingerprint sensor data obtained (914) is
processed to verify whether the obtained fingerprint data match the
stored fingerprint data of an authorized user of the locked mobile
device (926). When no match is found, the user request to access
the mobile device is denied and the fingerprint detection module is
switched back to the standby mode (902). When a match is verified,
the fingerprint detection module activates an optical detection
module including the light emitting sources and the photodetectors
to detect the presence of human heartbeat signals (928). Detecting
the presence of human heartbeat signal can be performed with or
without determining the actual heart beat rate. As described above,
the two optical wavelengths emitted by the light emitting sources
can be used to measure a user's heartbeat based on the oxygen level
in the blood due to pumping of the heart. This heartbeat
measurement offers an additional check on whether a live person is
associated with the detected human fingerprint.
[0082] When the presence of a heartbeat signal is detected (930),
the user request to access the locked mobile device is granted and
the fingerprint detection module is switched back to a standby mode
(932). Otherwise, the user request to access the locked mobile
device is denied and the fingerprint detection module is switched
back to the standby mode (902). Combining heartbeat detection with
the fingerprint detection provides an added layer of security to
the user authentication procedure.
[0083] FIG. 10 presents a flowchart illustrating another exemplary
process 1000 of authenticating user request to access a locked
mobile device in a high security mode based on a combination of
fingerprint detection and optical heartbeat detection.
[0084] A fingerprint detection module in a standby mode can
continuously monitors for a contact from an object with the
fingerprint detection module (1002). When the fingerprint detection
module detects a contact from an object with the fingerprint
detection module, the fingerprint detection module is used to
determine whether the detected contact is from human skin (1004).
In absence of contact from human skin, the fingerprint detection
module returns to standby mode and continues to monitor for another
contact (1002). When a contact from human skin is detected, the
fingerprint detection module obtains data from the object making
contact to determine whether the data from the object resembles
human fingerprint (1006). In absence of fingerprint detection, the
fingerprint detection module returns to standby mode and continues
to monitor for the next contact (1002). When the detected contact
is determined to be from human fingerprint, the main processing
unit attempts to authenticate the obtained fingerprint data to
determine whether the obtained fingerprint data match the stored
fingerprint patterns of an authorized user of the mobile device
(1008). When the obtained fingerprint data does not match with the
stored fingerprint pattern of the authorized user of the mobile
device, the fingerprint detection module returns to standby mode
and continues to monitor for the next contact (1002). When the
obtained fingerprint data match the stored fingerprint pattern of
an authorized user of the mobile device, the fingerprint detection
module determines whether the detected fingerprint of an authorized
user of the mobile device is associated with a live human by
detecting a presence of a heartbeat signal (1010). When the
presence of a heartbeat signal is detect, the user request to
access the locked mobile device is granted. When the presence of a
heartbeat is not detected, the user request to access the locked
mobile device is denied and the fingerprint detection module
returns to standby mode and continues to wait for the next contact
(1002). In various embodiments, the added verification of the
heartbeat signal detection associated with the authorized user
fingerprint detection at 1010 can be implemented as an optional
process and the user request to access the locked mobile device can
be granted or denied based solely on the detection of an authorized
user's fingerprint at 1008. In some implementations, the user
authentication process 1000 can directly obtain fingerprint data
from the object making contact without one or both intermediate
processes of identifying the detected contact as being from human
skin (1004) and determining whether fingerprints can be found on
the identified human skin (1006). In some other implementations,
the heartbeat detection process (1010) may be performed after
detecting a contact from an object (1002) but before determining
whether fingerprint data of an authorized user can be detected on
the human skin making contact with the touch sensor of the
fingerprint detector (1008).
[0085] FIG. 11A illustrates an exemplary fingerprint detection
module 1100 as a variation of fingerprint detection module 400 for
determining whether a detected contact from an object is from human
skin.
[0086] Similarly to fingerprint detection module 400, fingerprint
detection module 1100 includes substrate carrier 1102, protective
cover 1106, touch sensor such as a metal ring 1108 and sensor chip
1104, which may include a capacitive sense array for sensing a
fingerprint's ridge and valley patterns. Also, fingerprint
detection module 1100 includes one or more photodetectors 1116
which can either be integrated on sensor chip 1104 or separately
placed on substrate carrier 1102. The touch sensor for detecting a
contact from an object can be implemented using conductive material
having a shape corresponding to the fingerprint detection module,
such as a metal ring 1108 placed around and slightly above the
protective cover to protect the border of the protective cover. The
touch sensor can serve as a sensing electrode to detect a contact
from an object 1120 with the fingerprint detection module 1100. In
fingerprint detection module 1100, one or more light emitting
sources 1110 are located directly under protective cover 1106
within a gap between protective cover 1106 and substrate carrier
1102 and close to an edge of sensor chip 1104. Thus, unlike the
fingerprint detection module 400, the metal ring 1108 in
fingerprint detection module 1100 does not include a cavity for
housing the light emitting sources 1110. In some implementations,
light emitting sources 1110 can emit at least two different
wavelengths.
[0087] To allow detection light signals emitted from light emitting
sources 1110 to pass through protective cover 1106 and reach object
1120, the protective cover 1106 is transparent to the detection
lights. When protective cover 1106 is coated with a colored layer
on the bottom surface to achieve a desired appearance, the colored
layer can be opaque to the wavelengths of lights emitted by light
emitting sources 1110, which are placed directly underneath the
colored layer.
[0088] FIG. 11B illustrates an exemplary fingerprint detection
module 1101 which includes a protective cover coated with a colored
layer. As can be seen in FIG. 11B, fingerprint detection module
1101 includes substrate carrier 1102, sensor chip 1104, protective
cover 1106, metal ring 1108, one or more light emitting sources
1110 located underneath protective cover 1106, and one or more
photodetectors 1116. A colored layer 1112 is coated on the bottom
surface of protective cover 1106 to provide the intended color
appearance. The color layer 1112 is transparent to the light
emitted from light emitting sources 1110 to allow the emitted light
to pass through the colored layer 1112 and reach an object making
contact with protective cover 1106. Moreover, the color layer 1112
is transparent to reflected light from the object making contact
with the protective cover 1106 to reach photodetectors 1116 which
is also located underneath colored layer 1112. In the embodiment
shown in FIG. 11B, transparency to emitted light and reflected
light is achieved using multiple micro-holes 1114 created through
colored layer 1112 in the regions directly above light emitting
sources 1110 and photodetectors 1116. These micro-holes 1114 can be
sufficiently small so that they are not visible to a user but large
enough to allow emitted light from light emitting sources 1110 to
pass through and reach an object and reflected light from an object
to pass though and reach photodetectors 1116. For example, the size
of the multiple micro-holes can be from about 1 .mu.m to a few
.mu.m. In some implementations, micro-holes 1114 are formed in the
colored layer 1112 using a laser.
[0089] In various embodiments of a fingerprint detection module
described in this patent document (i.e., fingerprint detection
modules 100, 300, 400, 1100, and 1101), the fingerprint sensor chip
in a respective fingerprint detection module can have a thickness
between 200 .mu.m to 500 .mu.m. The substrate in a respective
fingerprint detection module can have a thickness between 0.5 mm to
2 mm. The metal ring in a respective fingerprint detection module
can have a thickness between 0.5 mm to 2 mm. The thickness of the
protective cover in a respective fingerprint detection module can
be between 100 .mu.m to 500 .mu.m. The protective cover, e.g.,
protective cover 106, can be made of entirely by a single material,
e.g., sapphire, zirconia, or ceramic. However, in some
implementations, a protective cover can be made of at least two
layers: a top layer of a relatively hard and more expensive
material of high dielectric-constant (e.g., sapphire, zirconia, or
diamond-like carbon) and a bottom layer of relatively less
expensive material of high dielectric-constant (e.g., a ceramic
material such as aluminum nitride (AlN)). For example, if a
protective cover has an overall thickness of 450 .mu.m, the top
layer can be made of 150 .mu.m of sapphire and the bottom layer can
be made of 300 .mu.m AlN. Such double layer structure can lower the
overall cost of the protective cover while maintaining sufficiently
high hardness and dielectric strength.
[0090] FIG. 12 presents a diagram of an exemplary fingerprint
detection system 1200 for performing human fingerprint detection
and authentication. As shown in FIG. 12, fingerprint detection
system 1200 includes a touch sensing module 1202 which includes a
touch sensor (such as a metal ring) and sensor circuitry for
detecting a contact from an object with fingerprint detection
system 1200. Also, fingerprint detection system 1200 includes an
optical sensor module 1204, a fingerprint pattern sensor 1206, and
an authentication processor 1208. Touch sensing module 1202 is
communicatively coupled to optical sensor module 1204 to combine
sensor data from touch and optical sensors. When touch sensing
module 1202 detects a contact from an object, such as a finger,
touch sensing module 1202 activates optical sensor module 1204 to
perform fingerprint analysis. Optical sensor module 1204 produces
probe light at two or more different optical wavelengths to which a
person's skin produces different optical responses at the two or
more different optical wavelengths due to presence of blood in the
person's skin. An optical detection unit in the optical sensor
module 1204 receives a reflection or transmission of the probe
light from the object making contact to detect optical measurements
that represent reactions of the reflected probe light at the two or
more different optical wavelengths. The optical measurements of the
reflected probe at different wavelengths can be used to compute
values that are compared to standard or calibrated values for human
blood absorption to determine whether the detected contact is from
human skin. The computation, comparison, and determination of
reflected probe light operations can be performed by an on-chip
signal processing unit integrated with optical sensor module
1204.
[0091] Optical sensor module 1204 is communicatively coupled to
fingerprint pattern sensor 1206. When optical sensor module 1204
detects human skin as the object making contact, optical sensor
module 1204 activates fingerprint pattern sensor 1206. Fingerprint
pattern sensor 1206 includes a sensor array which obtains
fingerprint data and a fingerprint pattern processor that
determines whether the obtained fingerprint data resembles a human
fingerprint. Fingerprint pattern sensor 1206 is communicatively
coupled to authentication processor 1208. When fingerprint pattern
sensor 1206 detects a human fingerprint, fingerprint pattern sensor
1206 activates authentication processor 1208. Authentication
processor 1208 receives the obtained fingerprint data from
fingerprint pattern sensor 1206 and verifies whether the obtained
fingerprint data matches stored fingerprint data of an authorized
person's fingerprint pattern. Based on the verification outcome,
the authentication processor generates authorization decision 1210
to determine whether the user request to access the locked mobile
device is granted or denied.
[0092] In a high security operation mode, authentication processor
1208 can receive optical measurements at two or more optical
wavelengths from optical sensor module 1204, and used the optical
measurements to detect a presence of a human heartbeat signal. This
heartbeat detection offers an additional layer of security on
whether a live person is associated with the detected human
fingerprint. The authentication processor 1208 then generates
authorization decision 1210 based on both the result of fingerprint
authentication and the result of heartbeat detection.
[0093] FIG. 13A is a top-down view of an exemplary mobile device
1300 showing a touch sensor assembly packaged under a display
screen cover glass. The mobile device 1300 includes a display
screen cover glass 1310 with an exemplary thickness between
0.55.about.0.75 mm. The touch sensor assembly 1312 is packaged to
be disposed under the display screen cover glass 1310. FIG. 13B is
a cross sectional view of the mobile device 1300 cut along the line
A-A. A cross-sectional view of the display screen cover glass 1310
is shown with a cross-sectional view of the touch sensor assembly
section 1312 packaged or disposed under the display screen cover
glass 1310.
[0094] FIG. 13C shows a cross-sectional view of the touch sensor
assembly 1312 shown in FIGS. 13A and 13B packaged to be under or
flush with the display screen cover glass 1310. The display screen
cover glass 1310 can have a thickness between 0.55.about.0.75 mm.
The touch sensor assembly 1312 includes a sensor chip 1332 with an
exemplary thickness of 0.25 mm. The sensor chip 1332 is disposed
over a printed circuit board (PCB) 1334 having an exemplary
thickness between 0.3.about.0.5 mm. A filling material, such as
epoxy etc. 1340 can be disposed between the sensor chip 1332 and
the PCB 1334 to attach the sensor chip 1332 to the PCB 1334. A
sensor cover glass 1330 with an exemplary thickness of between
0.1.about.0.3 mm can be disposed over the sensor chip 1332. The
sensor cover glass 1330 can incorporate a desired color to achieve
a desired visual appearance. A flexible printed circuit (FPC)
connector 1336 can be glued onto the sensor cover glass 1330
between the sensor cover glass 1330 and the sensor chip 1332. The
sensor cover glass 1330 can have an exemplary thickness of
approximately 0.03 mm. In addition a filling material 1338, such as
epoxy etc. can be disposed between the FPC connector 1336 and the
sensor chip 1332. A metal layer 1342 can be bound to each side of
the sensor cover glass 1330 and connected to the TX of the sensor
chip 1330. One or more compressed solder balls 1346 can be disposed
on the edges of the sensor chip 1332 between the FPC connector 1336
and the sensor chip 1332. One or more solder balls 1344 can be
disposed between the FPC connector 1336 and the filling material,
such as epoxy etc. 1340 disposed over the PCB 1334.
[0095] The packaging of the touch sensor assembly shown in FIGS.
13A, 13B and 13C can be applied to fingerprint detection modules
100, 300, 400, 1100 and 1101 in addition to mobile devices 800 and
820.
[0096] In one aspect, a fingerprint detection module includes a
substrate carrier and a fingerprint sensor chip located on the
substrate carrier for collecting fingerprint data. The fingerprint
detection module also includes one or more light emitting sources
located on the substrate carrier and configured to emit detection
light comprising at least one wavelength. The fingerprint detection
module additionally includes at least one photodetection element
located on the substrate carrier and configured to receive and
detect at least a portion of the detection light which is reflected
off of an object making contact with the fingerprint sensor module.
The at least one photodetection element generates output signals in
response to the detected light, wherein the output signals are used
to determine if the object is human.
[0097] In some implementations, the at least one photodetection
element is integrated on the fingerprint sensor chip. For example,
the at least one photodetection element can be located at an edge
of the fingerprint sensor chip. In some other implementations, the
at least one photodetection element is separated from the
fingerprint sensor chip and located on a different area of the
substrate carrier.
[0098] In some implementations, the one or more light emitting
sources include one or more light emitting diode (LED) chips. The
one or more light emitting sources can emit the detection light in
response to the detection that an object is making contact with the
fingerprint sensor module. Moreover, the at least one
photodetection element can be configured to detect a portion of the
detection light which passes through the object making contact with
the fingerprint sensor module, wherein the detected light can be
used to determine a light absorption property of the object. The
one or more light emitting sources can be modulated light
sources.
[0099] In some implementations, the fingerprint sensor chip
includes a pixelated sensing element array and a signal processing
unit for processing the collected fingerprint data. The signal
processing unit can be configured to process two output signals
generated by the at least one photodetection element corresponding
to the at least one wavelength of light. For example, the signal
processing unit can compute a ratio of the two output signals and
compare the computed ratio with a predetermined value calibrated
for a human finger or human skin to determine if the object is
human.
[0100] In some implementations, the fingerprint detection module
additionally includes a protective cover placed over the
fingerprint sensor chip to protect the fingerprint sensor chip and
a metal ring placed around and slightly above the protective cover
to protect the border of the protective cover. The one or more
light emitting sources can be placed inside a cavity within the
metal ring, and to emit the detection light through one or more
windows located at the top of the metal ring. Furthermore, the
metal ring can serve as a sensing electrode to detect if the object
is making contact with the fingerprint sensor module.
[0101] In some implementations, the substrate carrier can have a
thickness between 0.5 mm to 2 mm. The fingerprint sensor chip can
have a thickness between 200 .mu.m to 500 .mu.m. The protective
cover chip can have a thickness between 100 .mu.m to 500 .mu.m. The
metal ring can have a thickness between 0.5 mm to 2 mm.
[0102] In another aspect, a fingerprint sensor module includes a
substrate carrier and a fingerprint sensor chip located on the
substrate carrier for collecting fingerprint data. The fingerprint
sensor module also includes a protective cover placed over the
fingerprint sensor chip to protect the fingerprint sensor chip. The
fingerprint sensor module additionally includes a high
dielectric-constant layer sandwiched between the protective cover
and the fingerprint sensor chip to separate the protective cover
and the fingerprint sensor chip. Moreover, at least one edge of the
fingerprint sensor chip is extended beyond the boundary of the high
dielectric-constant layer to create a space between the protective
cover and the fingerprint sensor chip for wire-bonding the
fingerprint sensor chip.
[0103] In some implementations, the high dielectric-constant layer
is made of a ceramic material having a dielectric constant greater
than 8. For example, the high dielectric-constant layer can be made
of a ceramic material having a dielectric constant between 20 to
30. The thickness of the high dielectric-constant layer can be
greater than 100 .mu.m.
[0104] In another aspect, a fingerprint sensor module includes a
substrate carrier and a fingerprint sensor chip located on the
substrate carrier for collecting fingerprint data. The fingerprint
sensor module also includes a protective cover placed over the
fingerprint sensor chip to protect the fingerprint sensor chip,
wherein at least one edge of the fingerprint sensor chip is
extended beyond the border of the protective cover to allow
wire-bonding directly over the at least one edge of the fingerprint
sensor chip without getting interference from the protective
cover.
[0105] In yet another aspect, a fingerprint sensor module includes
a substrate carrier and a fingerprint sensor chip located on the
substrate carrier for collecting fingerprint data. The fingerprint
sensor module also includes a protective cover placed over the
fingerprint sensor chip to protect the fingerprint sensor chip,
wherein the protective cover comprises at least two layers: a top
layer made of a hard and more expensive material of high
dielectric-constant and a bottom layer made of a less expensive
material of high dielectric-constant. The top layer can be
significantly thinner than the bottom layer.
[0106] In yet another aspect, a fingerprint detection module
includes a substrate carrier and a fingerprint sensor chip located
on the substrate carrier for collecting fingerprint data. The
fingerprint detection module also includes one or more light
emitting sources located on the substrate carrier and configured to
emit detection light comprising at least one wavelength. The
fingerprint detection module additionally includes at least one
photodetection element located on the substrate carrier and
configured to detect at least a portion of the detection light
which is reflected off of an object making contact with the
fingerprint sensor module, wherein output signals from the at least
one photodetection element in response to the detected light are
used to determine if the object is human. The fingerprint detection
module further includes a protective cover placed over the
fingerprint sensor chip to protect the fingerprint sensor chip.
Moreover, the fingerprint detection module includes a high
dielectric-constant layer sandwiched between the protective cover
and the fingerprint sensor chip to separate the protective cover
and the fingerprint sensor chip, wherein at least one edge of the
fingerprint sensor chip is extended beyond the boundary of the high
dielectric-constant layer to create a space between the protective
cover and the fingerprint sensor chip for wire-bonding the
fingerprint sensor chip.
[0107] In yet another aspect, a method for determining if an object
making contact with a fingerprint detection module is human is
described. The method includes the steps of: in response to the
detection of an object is making contact with the fingerprint
detection module, emitting detection light of at least two selected
wavelengths using one or more light emitting sources within the
fingerprint detection module; detecting at least a portion of the
detection light which is reflected off of the object making contact
with the fingerprint sensor module using at least one
photodetection element within the fingerprint detection module;
processing the output signals from the at least one photodetection
element corresponding to the two selected wavelengths; and
determining whether the detected object is human by comparing a
signal ratio corresponding to the two selected wavelengths with a
predetermined value of the same signal ratio calibrated from a
human.
[0108] Various examples of fingerprint detection modules and
fingerprint sensor modules described in this patent document can be
integrated with mobile devices (e.g., smartphones, tablets,
laptops), computing devices (e.g., personal computers), and other
electronic devices to perform fingerprint authentication processes
on these devices.
[0109] Techniques, systems, and devices are disclosed for
performing human fingerprint detection and authentication using an
optical detection module in addition to a fingerprint pattern
recognition sensor. The disclosed human fingerprint detection and
authentication technology can be integrated with mobile devices
(e.g., smartphones and tablets) and other devices (e.g., such as
computer monitors) to improve the fingerprint authentication
technology used in existing devices.
[0110] While this patent document contains many specifics, these
should not be construed as limitations on the scope of any
invention or of what may be claimed, but rather as descriptions of
features that may be specific to particular embodiments of
particular inventions. Certain features that are described in this
patent document in the context of separate embodiments can also be
implemented in combination in a single embodiment. Conversely,
various features that are described in the context of a single
embodiment can also be implemented in multiple embodiments
separately or in any suitable subcombination. Moreover, although
features may be described above as acting in certain combinations
and even initially claimed as such, one or more features from a
claimed combination can in some cases be excised from the
combination, and the claimed combination may be directed to a
subcombination or variation of a subcombination.
[0111] Similarly, while operations are depicted in the drawings in
a particular order, this should not be understood as requiring that
such operations be performed in the particular order shown or in
sequential order, or that all illustrated operations be performed,
to achieve desirable results. Moreover, the separation of various
system components in the embodiments described in this patent
document should not be understood as requiring such separation in
all embodiments.
[0112] Only a few implementations and examples are described and
other implementations, enhancements and variations can be made
based on what is described and illustrated in this patent
document.
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